Single phase induction motors of the type commonly used with air conditioner and cooling equipment compressors generally require some type of auxiliary start capacitor for starting the motor. If the motor is a permanent split capacitor motor, i.e. one that has a run capacitor permanently connected across the run and start windings the motor, the start capacitor is connected in parallel with the run capacitor. The start capacitor, also sometimes referred to as a “hard start capacitor,” is connected for a short period of time to start the motor, and the start capacitor is disconnected from the motor near or at the time the motor achieves its run speed. This time is generally on the order of 50-100 milliseconds. Therefore, the start capacitor is wired in series with contacts for disconnecting it. The contacts can be a part of a potential or control relay, or an electronic relay.
If the start capacitor or the relay controlling it fails, the motor will not start. It is then necessary to replace the start capacitor and control relay, and this generally must be accomplished at the site of the motor. For air conditioners and other cooling equipment, this site could be a home, an office, a warehouse or factory, store, or any other building. This complicates the task of replacing the start capacitor and its connecting relay, in that a wide variety of brands and sizes of air conditioning and cooling units are in use, and these units use start capacitors having a variety of capacitances. Therefore, unless a repairman has a replacement hard start kit available with the correctly sized start capacitor, the repairman cannot complete repair without returning to a shop or parts distributor that has an inventory of hard start capacitor replacement parts.
Having to return to a shop or parts distributor in order to obtain the necessary materials to complete a repair is inefficient and time consuming and also delays the time that the customer's cooling system can be returned to operation.
Therefore, it would be advantageous if a repairman could carry one hard start replacement unit that is adaptable to many air conditioning units, cooling units, or other equipment utilizing single phase motors requiring a start capacitor, so that the repairman could adapt the hard start replacement unit to the requirements at hand and complete the repair in a timely manner.